The combination of combination locks used on attache cases and similar articles is generally a three- or four-digit number which must be formed, generally in a window, by correct positioning of movable elements, for instance wheels. This number, which generally is known only to the owner of the attache case, is visible upon the opening and upon the closing by combination of the lock and generally remains visible between these two operations, frequently for a relatively long period of time, for instance for the duration of a meeting, either because the owner or the attache case does not think of scrambling the combination after opening or in order, not by scrambling it, to clearly give evidence of a certain distrust of those with whom he is speaking or, merely very simply, in order to avoid having to reform the combination upon the closing of the lock.
However, it is obvious that under these circumstances combination locks practically lose their entire reason for existence since in this way the possibility is afforded meddlesome persons of at a propitious moment opening the attache case without breaking into it, and taking note of the frequently confidential documents which it may contain.